Iron-based amorphous alloys and methods of synthesizing iron-based amorphous alloys

ABSTRACT

A method according to one embodiment includes combining an amorphous iron-based alloy and at least one metal selected from a group consisting of molybdenum, chromium, tungsten, boron, gadolinium, nickel phosphorous, yttrium, and alloys thereof to form a mixture, wherein the at least one metal is present in the mixture from about 5 atomic percent (at %) to about 55 at %; and ball milling the mixture at least until an amorphous alloy of the iron-based alloy and the at least one metal is formed. Several amorphous iron-based metal alloys are also presented, including corrosion-resistant amorphous iron-based metal alloys and radiation-shielding amorphous iron-based metal alloys,

RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 12/426,769, filed Apr. 20, 2009 and entitled “Iron-BasedAmorphous Alloys and Methods of Synthesizing Iron-Based AmorphousAlloys,” which is herein incorporated by reference.

The United States Government has rights in this invention pursuant toContract No. DE-AC52-07NA27344 between the United States Department ofEnergy and Lawrence Livermore National Security, LLC for the operationof Lawrence Livermore National Laboratory.

FIELD OF THE INVENTION

The present invention relates to iron-based alloys, and moreparticularly to iron-based amorphous alloys and methods of synthesisthereof.

BACKGROUND

Prevention of corrosion and methods and techniques of preventingcorrosion are of great interest in many different industries and acrossmany different fields. One such field is military applications, wherecorrosion resistant materials are applicable to the protection ofmilitary vehicles such as tanks, transports, helicopters, andairplanes., Perhaps more importantly, corrosion resistance is crucial innaval vessels and submarines, which come in contact with seawater. It isknown that corrosion resistance can be improved by the used ofstructurally designed materials in the amorphous state where the atomsare arranged in a non-periodic fashion. In general, corrosion propertiesare attributed to both the atomic level and the microstructure level. Atthe atomic level, periodic defects exist which may create pathways forattack by ionic oxygen, nitrogen and/or hydrogen, which can travelthrough the crystal without significant obstruction. Grain boundariesand voids exist in crystalline materials, which are avenues for chemicalattack into materials, substantially lowering their corrosionresistance. Crystalline materials often have anisotropic thermalexpansion properties Thermal cycling can change microstructures,resulting in additional grain boundaries, dislocations, fractures andvoids, which can initiate stress corrosion cracking.

In amorphous metals, also called metallic glasses when prepared from themolten state, atomic arrangements are essentially random. Changes in theprecise atomic locations do not significantly affect materialproperties. In these structures, thermal expansion can be highlyisotropic, and grain boundaries and other defects can be eliminated.These structural changes mitigate stress corrosion cracking, andincrease corrosion resistance. even though local short range chemicalorder does occur in amorphous materials. Amorphous materials can beelementally tailored to specific applications. Since amorphous materialsdo not have a sharply defined melting point, they can be heat-softenedand mechanically shaped. Metallic glasses often exhibit extraordinarymechanical and thermal properties, magnetic behavior, and corrosionresistance.

High-iron amorphous metal alloys containing minor amounts of otherelements have been designed for corrosion resistant applications. Theatomization process used to prepare large quantities of iron-basedamorphous alloys is compositionally limited due to restraints on thecooling rate necessary to achieve an amorphous state. This is called thecritical cooling rate (CCR). When the CCR is not achieved, somecrystallization occurs. Only a particular compositional range caneffectively yield amorphous solids using conventional fabricationtechniques.

Iron-based amorphous alloys have been produced by various techniques,for example, by atomization, melt spinning, and casting. The materialmixtures are first melted and then quickly quenched to room temperature.The required CCRs are normally 10⁴ to 10¹¹ Kelvin per second in order toachieve an amorphous structure. Atomized powders are thermal spraycoated onto substrates using the high-velocity oxy-fuel (HVOF) process.Melt-spun ribbon samples of the same materials have also been preparedfor testing purposes. Corrosion testing of iron-based amorphous ribbonssuggests that corrosion resistance can be improved by increasing thealloy molybdenum content. However, it has heretofore been impossible tocreate an amorphous alloy with an appropriately high molybdenum contentdue to the high CCRs that are required.

Thus, current methods of amorphous alloy production are limited in whatcomposition can be formed due to the process employed and the inherentrequirement of high CCR. Therefore, it would be very beneficial toprovide more flexibility in the composition of iron-based amorphousmetal alloys by employing a more robust process of formation, resultingin more useful and previously unavailable coatings and/or structureswith enhanced mechanical and/or thermal properties, magnetic behavior,and corrosion resistance.

SUMMARY

A method according to one embodiment includes combining an amorphousiron-based alloy and at least one metal selected from a group consistingof molybdenum, chromium, tungsten, boron, gadolinium, nickelphosphorous, yttrium, and alloys thereof to form a mixture, wherein theat least one metal is present in the mixture from about 5 atomic percent(at %) to about 55 at %; and ball milling the mixture at least until anamorphous alloy of the iron-based alloy and the at least one metal isformed.

An amorphous iron-based metal alloy according to one embodiment includesbetween about 10 atomic percent (at %) and about 50 at % iron; betweenabout 0 at % and about 25 at % of a metal selected from a groupconsisting of manganese, carbon, silicon, zirconium, and titanium; andat least one of the following constituents:

-   -   between about 15 at % and about 30 at % of at least one metal        selected from a group consisting of molybdenum, tungsten,        gadolinium, nickel phosphorous, yttrium, and alloys thereof;    -   between about 20 at % and about 55 at % chromium; and    -   between about 20 at % and about 55 at % boron.

A corrosion-resistant amorphous iron-based metal alloy according toanother embodiment includes between about 10 atomic percent (at %) andabout 50 at % iron; between about 15 at % and about 25 at % molybdenum;and between about 0 at % and about 25 at % of a metal selected from agroup consisting of chromium, manganese, tungsten, carbon, boron,silicon, zirconium, and titanium.

A radiation-shielding amorphous iron-based metal alloy according to oneembodiment includes between about 10 atomic percent (at %) and about 50at % iron; between about 20 at % and about 55 at % boron; and betweenabout 0 at % and about 25 at % of a metal selected from a groupconsisting of chromium, manganese, molybdenum, tungsten, carbon,silicon, zirconium, and titanium.

Other aspects, embodiments, and advantages of the present invention willbecome apparent from the following detailed description, which, whentaken in conjunction with the drawings, illustrate by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an XRD spectra of SAM2X10 with increasing milling time.

FIG. 2 shows an XRD spectra of milled SAM2X5 powder as a function oftime.

FIG. 3 shows an XRD spectra of SAM2X25 with increasing milling time.

FIG. 4 shows XRD patterns of SAM1651 additions, with each curverepresenting the result of boron additions.

FIG. 5 shows Table 1, the listing of atomic % composition of SAMadditions.

FIG. 6 shows Table 2, the atomic % of SAM1651 additions.

DETAILED DESCRIPTION

The following description is made for the purpose of illustrating thegeneral principles of the present invention and is not meant to limitthe inventive concepts claimed herein. Further, particular featuresdescribed herein can be used in combination with other describedfeatures in each of the various possible combinations and permutations.

Unless otherwise specifically defined herein, all terms are to be giventheir broadest possible interpretation including meanings implied fromthe specification as well as meanings understood by those skilled in theart and/or as defined in dictionaries, treatises, etc.

It must also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an” and “the” include pluralreferents unless otherwise specified.

In one general embodiment, a method includes combining an amorphousiron-based alloy and at least one metal selected from a group consistingof molybdenum, chromium, tungsten, boron, gadolinium, nickelphosphorous, yttrium, and alloys thereof to form a mixture, wherein theat least one metal is present in the mixture from about 5 atomic percent(at %) to about 55 at %, and ball milling the mixture at least until anamorphous alloy of the iron-based alloy and the at least one metal isformed.

In another general embodiment, an amorphous iron-based metal alloycomprises between about 10 at % and about 50 at % iron, between about 0at % and about 25 at % of a metal selected from a group consisting ofmanganese, carbon, silicon, zirconium, and titanium, and at least one ofthe following constituents: between about 15 at % and about 30 at % ofat least one metal selected from a group consisting of molybdenum,tungsten, gadolinium, nickel phosphorous, yttrium, and alloys thereof,between about 20 at % and about 55 at % chromium, and between about 20at % and about 55 at % boron.

In another general embodiment, a corrosion-resistant amorphousiron-based metal alloy comprises between about 10 at % and about 50 at %iron; between about 15 at % and about 25 at % molybdenum; and betweenabout 0 at % and about 25 at % of a metal selected from a groupconsisting of chromium, manganese, tungsten, carbon, boron, silicon,zirconium, and titanium.

In another general embodiment, a radiation-shielding amorphousiron-based metal alloy comprises between about 10 at % and about 50 at %iron; between about 20 at % and about 55 at % boron; and between about 0at % and about 25 at % of a metal selected from a group consisting ofchromium, manganese, molybdenum, tungsten, carbon, silicon, zirconium,and titanium.

According to some embodiments, mechanical alloying techniques may beused to change the composition of iron-based amorphous alloys. Thischange is often very useful in many applications, because not only isthere a need for the material to be amorphous; but also, the materialmay be tuned to enhance certain critical properties, for examplecorrosion resistance, neutron absorbance, hardness, etc.

Iron-based alloys may include many elements, for example, iron (Fe),chromium (Cr), manganese (Mn), molybdenum (Mo), tungsten (W), carbon(C), silicon (Si), zirconium (Zr), titanium (Ti), and/or others. Otherelements may be added at many occasions in the processing, possibly as aprocessing aid. In principle, using the techniques presented herein, theamorphous structure for a specific material may be produced. However,not all the amorphous materials are alike and not all the iron-basedamorphous alloys are alike. The composition for each element may be afunction of the desired defined properties. Similarly, the resultantmaterial properties are in part controlled by the atomic compositions.These materials are of considerable interest because of the improvementin corrosion resistance for several reasons. One reason might be thelack of atomic ordering resulting in the absent of grain boundaries,which often are the weakest regions of the material. Possibleapplications for these materials are in areas of coatings to protectsurfaces, pipes, tanks, components, vessels, etc.

SAM2X5 which has the composition ofFe_(49.7)Cr_(17.7)Mn_(1.9)Mo_(7.4)W_(1.6)C_(3.8)Si_(2.4) and SAM1651with the composition ofFe_(49.1)Cr_(14.6)Mo_(13.9)B_(5.9)C_(14.0)Si_(0.3)Y_(1.9)Ni_(0.2), havebeen studied and the results of the studies have been included in thesection called Experimental Results, below. Prior art materials whichfeature amorphous characteristics have been prepared by atomization andmelt spinning. In these cases, the materials are initially physicallymixed, thermally excited by heating to a completely molten (liquid)state, and quickly cooled down. It has been reported that the requiredCCR (critical cooling rate) has to be in the range of 10⁴-10⁶° K./sec,otherwise the amorphous structure will not be formed. Without the propercooling rate, there is a tendency for the material to crystallize andhence the amorphous nature and the amorphous properties of the materialswill not be achieved. At times, small amounts of other compounds, forexample Yttrium, may be added to lower the CCR. The range of iron-basedamorphous materials that can be produced by these methods are clearlydefined by CCR and the ability of the elements not to crystallize.Unfortunately, the range of compositions that can be formed by thesemethods is very limited. The approaches presented herein overcome theselimitations, thereby providing new methods and materials.

According to some embodiments, the technique of mechanical alloying maybe used to extend the compositional variations of the iron-basedamorphous structure. In one embodiment, a high energy milling techniqueuses high energy ball collisions with the constituent materials inhardened steel vials to generate localized deformation and melting ofthe material particles. Standard commercial ball milling equipment maybe used, but application specific ball milling equipment may bedeveloped for use with the inventive processes. After impact-generatedlocalized heating occurs, and because the particles are in contact withthe mass of the vial and the balls, the material is quickly quenched tothe vial temperature. The vial must be kept cool, e.g., at a temperaturesufficient to impart the appropriate CCR. This technique ensures thatthe materials do not have enough time to crystallize.

With continuing milling for an appropriate amount of time, the materialmay then be examined and verified that it is still amorphous. Nocrystallinity is developed during the mechanical alloying processdescribed above.

According to some embodiments, a method of forming amorphous alloys mayemploy the use of high energetic deformation via the use of ball millingto introduce different compositions of molybdenum into an atomizediron-based amorphous alloy. In one approach, molybdenum was chosen as astarting addition into SAM2X5 powders; however, this technique can beextended to the addition of chromium, tungsten, and/or other metals andalloys of chromium, tungsten, molybdenum, and/or other metals.

With the addition of boron in high concentrations in some embodiments,or rather with high concentration of boron, the material will not onlyhave better corrosion resistance, but it will also act as a good neutronabsorber. To accomplish this, the elemental compositions of the alloycan be changed without changing the amorphous nature of the material. Inone approach, boron powder may be mixed into a SAM1651 matrix with thegoal of increasing the neutron absorption property and potentialapplication in waste containers, such as those used in the Department ofEnergy's Yucca Mountain Project.

According to one embodiment, a method includes combining an amorphousiron-based alloy and a metal or metals to form a mixture. The one ormore metal is selected from a group consisting of molybdenum, chromium,tungsten, boron, gadolinium, nickel phosphorous, yttrium, and alloysthereof Also, the one or more metal is present in the mixture from about5 at % to about 55 at %. The method also includes ball milling themixture for a period of time that is long enough for an amorphous alloyof the iron-based alloy and the one or more metal to be formed. Suchamount of time may be readily determined by one practicing the inventionand periodically examining the material in the mill for the desiredcomposition and amorphous state. In further approaches, the length oftime in which the ball milling is performed may be longer than the timeit takes to form the amorphous alloy.

In some embodiments, the iron-based alloy may be a product ofatomization, e.g. SAM2X5 or SAM1651, etc. If the iron-based alloy isSAM1651, according to some approaches, the amorphous alloy of theiron-based alloy and the one or more metal may include boron, which maybe present at greater than about 8 at %, or may be present at betweenabout 10 at % and about 53 at %. Of course, boron may be present athigher and/or lower at % as well.

In other embodiments, the amorphous alloy of the iron-based alloy andthe one or more metal may be at least about 80 at % amorphous, morepreferably at least about 90 at % amorphous, even more preferably atleast about 95% amorphous. The more amorphous the alloy of theiron-based alloy and the one or more metal is, the more useful it can bein some applications. Therefore, it is desirable to achieve a high levelof amorphousness in the alloy of the iron-based alloy and the one ormore metal.

In some approaches, an x-ray diffraction pattern of the amorphous alloyof the iron-based alloy and the one or more metal may show no sign of acrystalline form of the one or more metal. The x-ray diffraction patternof the corrosion-resistant amorphous iron-based metal alloy may alsoshow no sign of a crystalline form of other constituents. In furtherapproaches, the amorphous alloy of the iron-based alloy and the one ormore metal may comprise molybdenum which may be present at greater thanabout 9 at %; alternatively the molybdenum may be present at betweenabout 12 at % and about 27 at %.

In yet another embodiment, an amorphous iron-based metal alloy comprisesbetween about 10 at % and about 50 at % iron, between about 0 at % andabout 25 at % of a metal selected from a group consisting of manganese,carbon, silicon, zirconium, and titanium. The amorphous iron-based metalalloy also comprises at least one of the following constituents: betweenabout 15 at % and about 30 at % of at least one metal selected from agroup consisting of molybdenum, tungsten, gadolinium, nickelphosphorous, yttrium, and alloys thereof, between about 20 at % andabout 55 at % chromium, and between about 20 at % and about 55 at %boron.

In some embodiments, the at least one constituent may be molybdenum. Themolybdenum may be present in the alloy at between about 15 at % andabout 30 at %. Of course, other constituents may be used, and theconstituents may be present in any atomic percent. Also, if theconstituent is molybdenum, it may be present in atomic percentages ofgreater than 30 at % and 15 at %.

In more embodiments, the at least one constituent may be boron,chromium, or some other element.

A corrosion-resistant amorphous iron-based metal alloy, according toanother embodiment, comprises between about 10 at % and about 50 at %iron, between about 15 at % and about 25 at % molybdenum, and betweenabout 0 at % and about 25 at % of a metal selected from a groupconsisting of chromium, manganese, tungsten, carbon, boron, silicon,zirconium, titanium, and alloys thereof

According to some approaches, the iron may be present at between about40 at % and about 50 at %. Of course, the iron may also be present atgreater or less atomic percent. In some further approaches, themolybdenum may be present at between about 12 at % and about 27 at %.

In more approaches, an x-ray diffraction pattern of thecorrosion-resistant amorphous iron-based metal alloy may show no sign ofa crystalline form of the molybdenum. The x-ray diffraction pattern ofthe corrosion-resistant amorphous iron-based metal alloy may also showno sign of a crystalline form of other constituents.

A radiation-shielding amorphous iron-based metal alloy comprises, insome embodiments, between about 10 at % and about 50 at % iron, betweenabout 20 at % and about 55 at % boron, and between about 0 at % andabout 25 at % of a metal selected from a group consisting of chromium,manganese, molybdenum, tungsten, carbon, silicon, zirconium, andtitanium.

In further embodiments, the iron may be present at between about 25 at %and about 40 at %. Of course, the iron may be present in greater or lessatomic percent in the radiation-shielding amorphous iron-based metalalloy. In addition, the boron may be present at between about 10 at %and about 53 at %. Of course, the boron may be present in greater orless atomic percent in the radiation-shielding amorphous iron-basedmetal alloy.

Experiments

The samples used for the experiments are listed in Table 1 in FIG. 5.For historical reasons, the SAM samples originated from SAM40. Forexample, SAM2X5 comprises 95 at % of SAM40 and 5 at % of Mo.Consequently, SAM2X10 comprises 90 at % of SAM40 and 10 at % of Mo andso forth. Table 1 also tabulates the atomic percentage of each element.To reduce the milling time, the starting matrix material of SAM2X5 andSAM1651 powders were prepared by the atomization technique. Two batchesof molybdenum powder samples having a particle size of roughly 60 μmwere used. The powder matrix samples of SAM2X5 and SAM1651 are amorphousas characterized by the x-ray diffraction technique.

Table 2 in FIG. 6 shows the atomic composition for SAM1651 additions andthe amount (in grams) of boron that was added into 2 grams of the matrixsample. The milling process was carried out using the Spex800D Mil/Mixerwith 2 hardened steel vials.. Various numbers of 316 and 440 stainlesssteel balls of different sizes were used in the ball miller. Duringprocessing, the vials were kept cool using an in-house air system. Threebatches of 1, 1½, and 2 grams of SAM2X5 matrix powder were used and theamount of molybdenum by weight to be added was calculated and is listedin Table 2 in FIG. 6. The batches, the number of balls used, and themilling times were closely monitored, recorded, and optimized to achievean amorphous mixture, to reduce the milling time, and to increase thequantity of the resulting powders. Typically, twelve 5/16″ balls (316SSand 440SS) with 2 grams of matrix powder and molybdenum or boron powdersadded. A milling time of about 16 hours resulted in total conversion ofthe mixture to a fully amorphous structure. The milling time can beshortened if the amount of matrix powders is reduced or the number ofballs is changed. Typically, the powders are loaded into the vials inair. In situations where oxidation can easily occur, the loading shouldbe carried out in a controlled inert atmosphere, such as in a glove box,clean room, etc. The resulting powders were then characterized using theXRD technique and crystalline metal oxides were not observed.

The X-ray diffraction experiments were carried out using theconventional Philips vertical goniometer utilizing Cu Ka radiation. Ananalyzing diffracted beam monochromator was used for energydiscrimination. The scans were performed from about 20° to about 80°(2θ) with a 0.02° (2θ) step size at 4 second counting intervals perstep. The powder material was loaded onto a special glass holder toavoid any scattering effects. The amorphous peak from the glass holderwas located at about 20° to about 25° (2θ). In most cases, there weresufficient amounts of sample such that the scattering signal from theholder was negligible.

Experimental Results

The results of molybdenum additions to SAM2X5 are discussed below. Aftermilling, the powder samples were carefully monitored and unloaded toavoid contamination. Typically, the resulting powder is black in colorand very fine. SAM2X5 has a rounded particle shape which is typical ofmaterials prepared by an atomization technique. The resultant milledpowder is much finer and has irregular particle sizes of a few micronscompared to the coarser atomized sample.

FIG. 1 shows the diffraction patterns of milled SAM2X10 powders atmilling times of 0, 0.5, 5 and 7 hours. The curves are normalized foreasy viewing. The starting physical mixture without milling is shown inthe lowest pattern, indicating the presence of a crystalline componentmixed with the amorphous SAM2X5. The three crystalline peaks can beindexed to cubic molybdenum. As it can be observed, the peak heightsdecrease as the milling time increases. The reduction in the peaks (andeventual disappearance) indicates that all of the components in thematerial, Mo and SAM2X5 are mixed at the atomic level and have becomeamorphous. It is interesting to note that the disappearance of Mo peaksis not totally due to the breakdown of the Mo crystals intonano-crystalline structures. This is because the Mo peaks diminish bylosing intensity rather than by the increase in peak widths. The millingof SAM2X5 does not result in crystalline phases. Initial reduction ofparticle size can be observed by the peak broadening from the un-milledto the 0.5 hour milled sample.

To ensure that there are no changes in SAM2X5, neat matrix materialswere also milled and the results are shown in FIG. 2, indicating anabsence of any change in crystallinity. Therefore, milling the amorphousSAM2X5 did not generate any crystallinity; however, the particle sizehas been changed as the result of ball milling.

Similar curves are obtained for SAM2X15 and SAM2X20 after some millingtime. As listed in Table 1, SAM2X10, SAM2X15, SAM2X20 and SAM2X25 have12, 17, 22, and 27 atomic % (at %) of molybdenum at concentration. FIG.3 shows the resulting diffraction pattern for SAM2X25 which has as muchas 27 at % of Mo. Clearly, it can be observed that with increasingmilling time, the intensity of Mo peaks is reduced significantly. Duringthe initial milling period, the results suggest that the crystallinemolybdenum particles break down into nano-crystallites, as evidenced bythe broadening of the Mo peak.

On continuing milling, these peaks diminish, suggesting that thecrystalline Mo is incorporated into the SAM2X5 matrix, resulting inSAM2X25. Neat molybdenum powders were also processed using themechanical alloying technique with the same processing parameters, thatis, the same number of balls, amount of powder, and milling time. Theresult indicates the presence of crystalline Mo peaks, but the peaks arebroader, suggesting that neat Mo cannot be made amorphous through theball milling technique.

The addition of boron into SAM1651 is discussed below. The addition isdetermined using the calculations in Table 2. The concentrations foreach percentile are calculated based on atomic percent. As calculated,the amount by weight that may be added into 2 grams of SAM1651 is shownin the bottom row. Clearly, the addition of boron resulted in anamorphous structure even up to 25 at % of boron as shown in FIG. 4.Presently, the analysis cannot fully confirm that the boron atoms areincorporated into the SAM1651 matrix. This is because the X-rayscattering power of boron is significantly weaker than the other theelements used.

The technique of mechanical alloying allows the addition of otherelements into the amorphous matrix of SAM2X5 without developingcrystallinity. This is not possible by the atomization technique used inthe prior art because of the tendency of some elements to formcrystalline phases. Mechanical alloying is a particle deformationtechnique that uses high energy ball collisions. In fact, it has alsobeen argued that there is even instantaneous local melting with rapidquenching caused by the cold high mass sample vial. Since thetemperature of the vials is kept below the alloy glass transitiontemperature, the materials will not have sufficient energy tocrystallize. In some embodiments, as much as 27 at % molybdenum may beadded to SAM2X5 and the material may still remain amorphous.Furthermore, the concentration of SAM2X5 amorphous alloy can now betuned to enhance specific properties, through the addition of Cr, W,alloys of Cr, alloys of W, alloys of Mo, etc.

The addition of boron to SAM1651 can be useful for controllingcriticality and/or for providing radiation shielding in radioactivewaste storage canisters. It appears that the incorporation of boron intoSAM1651 yields amorphous alloys even up to the concentration of 50 at %boron. However, adding additional boron may be useful for someapplications but may have negative impacts, on other alloy physicalproperties such as the corrosion resistance and hardness. Hence, thistechnique, in some embodiments, allows material synthesis with preciseadjustment of the elemental compositions to fit a specific applicationwhile achieving an amorphous state.

The resultant powders from the mechanical alloying process may benanometers in size. According to some embodiments, this powder propertymay enhance the forming of high density amorphous bulk materials duringconsolation. Intuitively, the material may be conveniently pressed andannealed at an appropriately chosen temperature above the glasstransition temperature to avoid pores and void formation. In otherembodiments, sintering heat treatment may also be used because theparticles have been brought much closer together during the pressingprocess.

The embodiments described herein, and other embodiments not describedbut possible within the scope of the claims, may be useful for manydifferent applications. For example, the amorphous powder may befabricated to be used as a coating on components to enhance theircorrosion resistance. Also, by adding neutron absorbing elements, theresulting materials may be used as a coating for nuclear storage basketsand/or waste containers, such as those used in the Yucca MountainProject. There may be cost savings due to the use of the less expensiveiron rather than a more expensive component. It is also possible thatthe material may be used to coat vessels and/or components used insaltwater or under harsh conditions, such as military applications, toprevent and/or reduce corrosion.

The ability to tailor the elemental composition of the amorphous ironbased alloy is not necessarily limited to coatings. Using advancedpowder compaction technology, bulk parts can be molded using theseamorphous powders. Amorphous materials which lack discreet meltingpoints tend to soften over a wide range of temperatures. Unlikeconventional crystalline materials, this unique property enables thematerials to be conveniently molded and still retain their amorphousstructure.

Another property of amorphous materials is the formation of shear bandsduring impact. The shear band behavior allows for better absorption ofhigh energy projectiles into bulk parts, such as armor plates. This isoften described as a “self sharpening” phenomenon. The use of zirconiumbased amorphous metals with crystalline heavy metal wires has beendescribed in U.S. Pat. No. 6,010,580, which is hereby incorporated byreference. Iron based alloys can also be used in a similar fashion.Consequently, armor plates made from amorphous materials can slow downthe projectiles due to the shear band behavior. A successful employmentof this material can replace the presently used depleted uranium armorplates, thus avoiding the toxicity issues associated with theirproduction and disposal.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of a preferred embodiment shouldnot be limited by any of the above-described exemplary embodiments, butshould be defined only in accordance with the following claims and theirequivalents.

What is claimed is:
 1. A method, comprising: combining an amorphousiron-based alloy and at least one metal selected from a group consistingof molybdenum, chromium, tungsten, boron, gadolinium, nickelphosphorous, yttrium, and alloys thereof to form a mixture, wherein theat least one metal is present in the mixture from about 5 atomic percent(at %) to about 55 at %; and ball milling the mixture at least until anamorphous alloy of the iron-based alloy and the at least one metal isformed.
 2. The method of claim 1, wherein the iron-based alloy is aproduct of atomization.
 3. The method of claim 1, wherein the amorphousalloy of the iron-based alloy and the at least one metal is at least 90at % amorphous.
 4. The method of claim 1, wherein an x-ray diffractionpattern of the amorphous alloy of the iron-based alloy and the at leastone metal shows no sign of a crystalline form of the at least one metal.5. The method of claim 1, wherein the amorphous iron-based alloy isSAM2X5.
 6. The method of claim 5, wherein the amorphous alloy of theiron-based alloy and the at least one metal comprises molybdenum presentat greater than about 9 at %.
 7. The method of claim 5, wherein themolybdenum is present at between about 12 at % and about 27 at %.
 8. Themethod of claim 1, wherein the amorphous iron-based alloy is SAM1651. 9.The method of claim 8, wherein the amorphous alloy of the iron-basedalloy and the at least one metal comprises boron present at greater thanabout 8 at %.
 10. The method of claim 9, wherein the boron is present atbetween about 10 at % and about 53 at %.
 11. An amorphous iron-basedmetal alloy, comprising: between about 10 atomic percent (at %) andabout 50 at % iron; between about 0 at % and about 25 at % of a metalselected from a group consisting of manganese, carbon, silicon,zirconium, and titanium; and at least one of the following constituents:between about 15 at % and about 30 at % of at least one metal selectedfrom a group consisting of molybdenum, tungsten, gadolinium, nickelphosphorous, yttrium, and alloys thereof; between about 20 at % andabout 55 at % chromium; and between about 20 at % and about 55 at %boron.
 12. The amorphous iron-based metal alloy of claim 11, wherein theat least one constituent is molybdenum, wherein the molybdenum ispresent in the alloy at between about 15 at % and about 30 at %.
 13. Theamorphous iron-based metal alloy of claim 11, wherein the at least oneconstituent is boron.
 14. The amorphous iron-based metal alloy of claim11, wherein the at least one constituent is chromium.
 15. Acorrosion-resistant amorphous iron-based metal alloy, comprising:between about 10 atomic percent (at %) and about 50 at % iron; betweenabout 15 at % and about 25 at % molybdenum; and between about 0 at % andabout 25 at % of a metal selected from a group consisting of chromium,manganese, tungsten, carbon, boron, silicon, zirconium, and titanium.16. The corrosion-resistant amorphous iron-based metal alloy of claim15, wherein the iron is present at between about 40 at % and about 50 at%.
 17. The corrosion-resistant amorphous iron-based metal alloy of claim16, wherein the molybdenum is present at between about 12 at % and about27 at %.
 18. The corrosion-resistant amorphous iron-based metal alloy ofclaim 15, wherein an x-ray diffraction pattern of thecorrosion-resistant amorphous iron-based metal alloy shows no sign of acrystalline form of the molybdenum.
 19. A radiation-shielding amorphousiron-based metal alloy, comprising: between about 10 atomic percent (at%) and about 50 at % iron; between about 10 at % and about 55 at %boron; and between about 0 at % and about 25 at % of a metal selectedfrom a group consisting of chromium, manganese, molybdenum, tungsten,carbon, silicon, zirconium, and titanium.
 20. The radiation-shieldingamorphous iron-based metal alloy of claim 19, wherein the boron ispresent at between about 20 at % and about 53 at %.